Process of manufacturing soda



No Drawing.

FICE.

TOBANOSKE NISHIGAWA, OF TOKYO, JAPAN,

PROCESS OF MANUFACTURING- SODA.

To aZZ whom it may concern:

Be it known that I, TORANOS'KE NISHI- ,GAWA, subject of Japan, residingat No. 5,

ikawa Cho, Akasa-ka Ku, Tokyo, Japan, have invented new and usefulimprovements in Processes of Manufacturing Soda of which the followingis a specification.

This invention relates to improvements in'a process of manufacturingsoda and consists in first obtaining sodium bicarbonate by passingammonia and carbon dioXid into a solution /of sodium chlorid; then inadding sodium chlorid to the remaining liquor and causing the ammoniumchlorid contained therein to crystallize and precipitate by cooling thesaid remainingliquor While passing thereinto sufficient ammonia totransform the small amount of sodium and ammonium bicarbonates intonormal carbonates, the ammonia used being obtained by fixing thenitrogen contained in the Waste gases issuing from the carbonators andscrubbers. The object of this invention is to manufacture sodaeconomically by' transforming all the sodium chlorid, which accordingto'processes hitherto known, is being'thrown away, into sodiumbicarbonate and by utilizing at the same time the nitrogen contained inthe wastegases. According to the ammonia-soda process ashitherto-practised, of which the present invention is an improvement,asaturated solution of sodium ehlorid is caused to absorb ammonia gasinto which is passed carbon dioxid (containing nitrogen) issuing fromthe :lime kiln, and sodiiun bicarbonate is thus formed. The reactionwhich takes place is as follows chlorids, ammonia is recovered butsodium and calcium chloride are entirely thrown away. Thus, nearly onehalf of the sodium chlorid, together with calcium chlorid and more orless sodium bicarbonate is lost,

and the process cannot be commercially Specification of Letters Patent.

Patented. N (iv. 16, 1920.

Application filed September 30, 1919. Serial 2:10. 327,574.

worked unless at places-Where salt can be very cheaply obtained. v

According to my invention, in order to utilize the sodium cbloridcontained in'the mother liquor after filtering off sodium bicarbonate inthe above process, further sodium chlorid is added thereto, and ammo:mum chlorid is separated. therefrom by cooling the liquor and passingthereinto ammonia, which is obtained, not by distilling themother-liquor, but from gases issuing from the carbonators andsci'ubbersby fixing the nitrogen contained therein, as it is found thereis an almost pures'tat e. All'of the sodium chlorid remainingunconverted in the mother liquor, returning to the absorber after theaddition tothe liquor'of sodium chlorid, which is chemicallyequi valentto theeodium l'iicarbonate formed, is not lost and is eventuallyconverted into soda, while the ammonia is transformed into ammoniumchlorid, which is collected as a by-product. In this way, theammonia-soda process can be worked most' economically,

and the following is anexample' of carryingv my invention into practice.

Separate sodium bicarbonate formed by passing ammonia and carbon, dioxidinto a solution of sodium chlorid, item the process hitherto practised.To the Y mother liquor add sodium clilorid chemically equivalent to thesodium bicarbonate filtered oft". and cool the liquor to below 5 C. byany suitable refrigerating machine, adding thereto sutiicient ammonia toturn a small proportion oi bicarbonates remaining dissolved in theliquor into normal carbonates. The reaction in the carbonators beinggreater pa rt of the ammonium chlorid which NH,, to the product,

, exists in a large proportion, will crystallize and precipitate, and isfiltered off. In other words, in the common ammonla soda procremaining"to pmduce' bicz :rban

a w. .ini-o inol'msarboLate secmldary cm Aim Lust,

i chlm-icl soiuiion ands; selmmn 15; 709mg molcd,

be served, and :m' recovering aml'otaiiy aispensml with, bee cnl orin ascalcium chim'id carbonate, and. the reach I place 1s:-

. Jilin mvenumn il 0110 can. be repeatedly {it-Ilium; in me processuntil, it tetallv mm- SEEM-i.

Now, it :1

' k cooling .1 e

m; but 2.1023 1 m; 1

-1h r1n produced by decamposition bicmbm'umas,

of sad um 0110 1d IS mu sd to combine Wiih mm 21,1 1 {arm anmmnilmlchlerid, which is a. vamable my-product.

3. Sodium bicarlmnatg dissolved in "7 methar liquor which is usually10st inin procgass 9f 2*ec0ver.ing ammeniaby 0f 11mg and. steam in. theammonia, stilL'i c0 ted into sudinm c'hlorid and 21101). n carbonate,both of which remain in the, motherli um aft-gr precipitation 0f 1.;man: mlum mini-1d 1g returmzi is the as of dishin iiquur by -1 flung mmdispensed 01? s zs mnonia is 2. 3. invention, 110th- ;ost, and theammoniap Worked most economllt'rogen, 1d mu a process can be may pm 21g:20" 11 m U a Z1 of so,

(nimsiszfia in am ,ng in- 110 din'm ch'lm'id. after mdium biczubom iehas 1 fiitemd fz'let'efrom; in sodiu the said her liqum: whisa'pa figthelalinto snfii-- amnmnia t0 convert the bicm'bonves 1g dissolvedthera'in in normal (29% causmg ammomum ch rid i0 and rec .1mm; and 111115131;; the

0f SOdi'dln bicarbonate, substm aciding 1 m ereinbefora set forth.

7 301mm). It is only bet-Ween the. ammonia! bi. :arbonate and sodium(sill-arid am double decanposi- 72011 takes 'pmce, i Date 031' soon as1:116 @516 ate by passing ammonia, and carbonic acid into solutionaf'sedium chlorid, which wrnistsin cu-Ming ta 1% mother iiquoxpsw aftersodium bicaflwnate has rec tlmefrom; in. 006313155 the said SSS ass,about Ina/finer Eiquor as brine for the- "ne process of precipitatingsodium 0L 3. The process of precipitating sodium bicarbonate by passingammoniaand carbonic acid into solution of sodium ehloi'id which consistsin adding to the mother liquor sodium chlorid after sodium bicarbonatehas been filtered therefrom; in. cooling the said mother liquor whilepassing theremt sufiieient ammonia to convert the bionrbonates remainingdissolved therein to normal car- 10 bonates; in using the remainingmother bicarbonate; and. in fixing the nitrogen gas issuing from theearbonators, using the am- 'monia thus obtained in th production ofsodium bicarbonate according to the improved process, substantially. ashereinbefore set forth.

In testimony whereof I have signed my name to this s ecifioation.

TO AlOSKE NISHIGAVVA.

